100 Selectable frequencies on each channel, up to 20 units can be used simultaneously * Automatic transmitter setup, the channel of the transmitter and receiver can easily synchronize * Automatic frequency scanning to find and set the best available channel * Adjustable GAIN, adjust the GAIN to change the microphone sensitivity and eliminate FEEDBACK * Range: Up to 600 feet ( 200 meters ) Frequency: UHF 610MHz - 680MHz